Lubricating system for chain saws



July 17, 1962 1. w. oEHRLl LUBRICATING SYSTEM FOR CHAIN SAWS Filed May 2, 1960 mm. mi EW@ 01M wm M M 0M J M `W Unite tates McCulloch Corporation, Los Angeles, Calif.,` a corporation of Wisconsin Filed May 2, 1960, Ser. No. 25,931 3 Claims. (Cl. 143-32) This invention relates to lubrication of chain saws and more particularly it relates to a chain saw having incorporated therein a system -for directly lubricating the part of the chain saw carrying the cutters which are about to be moved into the cutting position on the underside of the saw blade.

It is an object of the present invention -to provide means in the saw blade to supply lubricating oil to that part of the chain at -iwhich the oil provides the maximum benet to prevent wear both on the saw blade and the saw chain.

It is still another object of the invention to provide a saw blade having a lubricating oil flow passage therein connectible at its inner end to a driving engine and extending longitudinally outwardly to supply oil to an outer end portion of the saw chain and to a wheel on the outer end of the blade on which the chain travels. lt has been .found in the practice of the invention that supplying oil directly to the wheel bearings and to the wheel on the outer end of the blade, and at the same time, to the chain as it eXes and passes over the wheel, just prior to its moving into its cutting position, has lengthened the life of saw yblades four times over that of blades which were not directly lubricated at their outer ends.

Another feature of the invention is that in supplying 'the oil directly to the bearings any foreign material which tends to work down the sides of the wheel between the .plates supporting it is flushed outwardly by centrifugal force created by the rotation of the wheel.

Another object of the invention is to lubricate the moving chain while the joints are iiexed on the wheel so that when the chain is straightened on the blade oil is carried to any previously unlubricated portions.

It is a yfurther object of the invention to provide a lubricating oil passage extending longitudinally from one end of the saw blade to the other and having two vertically spaced oil inlet ports at the inner end of the blade so that the blade can -be reversed on the saw engine by rotating it 180 about its longitudinal axis to prevent uneven wear of the blade. That is, all saw blades tend to wear on their underside toward the outer end where the chain passes over it during its cutting operation and thus, by providing means for reversing the blade, the blade life can be approximately doubled.

It is a still further object of the invention to provide a laminated saw blade in which a lubricating oil passage can be economically formed therein during manufacture and in which the blade is not required to be made thicker because of the lubricating oil passage. Lubricating oil passages can also be `formed in one piece saw blades, but these are more expensive to manufacture than a laminated blade having an equivalent oil passage.

Further objects and advantages of the invention may be brought out in the vfollowing part of the specication wherein the purpose of the explanation of details is to make a complete disclosure without, however, limiting the scopeY of the invention which is set Iforth in the appended claims.

Referring to the accompanying drawings which are for illustrative purposes only:

FIG. 1 is a side elevational view of a power-driven chain saw employing the invention;

FIG. 2 is an enlarged -fragmentary transverse section taken as indicated by the line 2-2 o'f FIG. l

atent 3,944,536 Patented July 17, 1962 FIG. 3 is a fragmentary transverse sectional view taken as indicated bythe line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary longitudinal sectional View taken as indicated by the line 4-4 of FIG. l;

fFIG. 5 is a sectional view, illustrating the laterally spaced lubricating oil ow passages which bridge the gap between the central plate of the saw blade and the wheel, taken as indicated by the line 5--5 of FIG. 4; and

FIG. 6 is a fragmentary side elevational view of the outer end of the saw blade and the ybearing mounted wheel.

Referring again to the drawings, there is illustrated in FIG. 1 a power-driven chain saw comprised generally of a power unit 10 having an engine therein 'for supplying power to rotate a drive shaft 11 on which is operably mounted a chain drive sprocket 12. A saw blade 13 is secured to a -lat mounting surface on the power unit 1t) forwardly of and in longitudinalalignment with a plane through the center of the sprocket and at right angles to its shaft by means of bolts 1'7. v

The endless chain 24 is comprised of alternate sideV and center links 26 and 30, respectively, connected by pintles 25. Selected side links have outwardly directed depth gauges 28 and cutting elements 29, not shown in detail. Each of the side links 26, positioned on opposite sides of the chain, has inwardly directed projections 27 so as to form pairs of opposite laterally spaced teeth adapted to travel on the blade 13 and on the engine-driving sprocket 12. The sprocket 12 is formed from two identical laterally aligned sprocket wheels spaced by a disc 35, the oppositely positioned projections being held in alignment on opposite sides of the disc and being of the proper size to fit between the teeth of the sprocket so that its rotation drives the chain.

For illustrative purposes, a laminated saw blade`13 is .Vice

shown formed by three elongated ilat plates7 namely, a

stantially coextensive longitudinally with the central plate at inner end 34 of the blade and transversely, or in the vertical direction in the drawings, the central plate 31 extends outwardly above and below the outer plates to form a tongue or chain track 38, the outer edges of which are in longitudinal alignment with the sprocket disc 35. Adjacent the inner end 34 of the blade is a longitudinal adjusting mounting slot 39 laterally through vthe blade and through which bolts 17 extend, lthe blade being movable longitudinally on the bolts `for adjustment purposes. -In assembling the blade and the chain on the power unit, the slot 39 is adjusted on the bolts so that the chain is properly positioned on the sprocket and on the blade. As shown in FIG. 2, the inner surface of the blade -formed by blade 33 is in contact 'with a llat mounting surface of the power unit, and on the outer sur-face of the outer plate 32 is a mounting plate y40, shown cutaway and in dotted lines in FIG. l and shown fragmentarily in FIG. 2. When the chain is properly adjusted as to tightness, nuts .41 are tightened on the bolts 17 so as to ixedly secure the blade on the mounting surface of the power unit 10.

At the outer end 42 of the blade the outer plates extend longitudinally beyond the central plate to form a mount for a chain guiding Wheel 46 having substantially the same lateral thickness of central plate 31 and being -in longitudinal and transverse alignment therewith to form a rotatable chain track at the outer end. The Wheel 46 is supported by a rivet-axle 47 secured to the two outer plates 32 and 33 and xed on the axle is a short sleeve or washer-shaped inner bearing race forming portion 43.

Y greater than the transverse width of 'the central plate 31 at its outer end, as the latter plate is tapered transversely inwardly to provide clearance for theV chain as it moves from the wheel onto the chain track 38A so as to eliminate any possible obstruction to the chain.`

The chain generally travels having a substantial portion of its center links 39 on the outer edge of the track 33 and on the circumferential edge of the wheel 46 soV that the inner ends of the projections 27 do not contact the outer plates 32 and 33. The movement of the chain thus causes the wheel to rotate and there is very little wear between the wheel and the chain from the movement of the one on the other. This arrangement provides the advantages of nonprecision manufacture of both the chain and the blade relative to length of the projections 27 and the transverse width of the track; that is, the basic tolerance limitation is only that the projections must be shorter than the transverse width of the track or vice versa.

The projections 27 engage the sprocket teeth and hold the chain on the track laterally. Thus, in operation, the sprocket rotates in the clockwise direction to move the chain outwardly from the engine over the top of the blade, over the wheel causing it to rotate, and the chain Ireturns toward the engine in its cutting position on the underside of the blade.

A lubricating oil system, not shown, is provided iny the power uni-t 19 to supply oil from the engine to the blade and chain. This system may be au automatic continuously operating one or it may be an intermittently operated automatic system or it'may be a hand operated plunger pump system, the latter two of which may be actuated, for example, by a thumb-operated knob or plunger 64, shown in FIG. 1. To carry lubricating oil from the engine, a duct 65 is provided to be in communication withv the oil passage means formed within the blade. As may be seen 4in FIGS.- l and 2, at the inner end 34 of the blade are two transversely or vertically spaced holes 66 and 67, extending laterally through the blade and each having a sintered metal lter-forming plug 70 therein. The sintered plug filters 70 are provided to prevent any foreign matter, such as sawdust, from entering the chain oiling system.

The upper hole 66 is positioned on the engine to receive the lubricating oil supply from the duct 65 and the lower hole 67 is sealed by the engine mounting surface on one side and by the mounting plate 40 on the other. As the blade is used in'one position on the engine, it tends to wear unevenly, especially at its outer end, and it is thus desirable to reverse Vit on the engine, as may be visualized in viewing FIG.' 2, so that the outer surface of plate 32 is in abutment with the engine-mounting surface and so that the outer surface of plate 33 is in abutment with'the mounting plate 40. WhenV the blade is so reversed, the hole 67 is in alignment with Vthe supply duct 65 and the hole 66 is sealed by the enginemounting surface on oneV side and the mounting plate ou the other,

Extending longitudinally outwardly through the central plate 31 from holes 66 and 67 are two converging passages 71 and 72, respectively, which join each other and a main longitudinal oil conduit or passage 73, conveniently formed by a channel-shaped groove in plate 31 and the inner seal-providing surface of plate 32.

As shown in FIGS. l, 4 and 6 passage 73 extends longitudinally outwardly to a point inwardly of the outer end of plate 31 and inwardly of gap 52, and terminates in a lateral bore 77 extending through the central plate. In

. 4 n communication with bore 77, laterally outwardly therefrom are longitudinally directed ducts 78 and 79, best seen in FIGS. V4, 5 and 6, which extend longitudinally outwardly so as to be in communication with the bearing race 80 formed between the race sleeve 48 and the inner circumferential surface of the wheel 46. Ducts 78 and 79 may be formed by conveniently cutting laterally inwardly facing channel-shaped grooves in the inner walls of the outer plates 32 and 33 and by inserting into the grooves laterally 'outwardly facing channel strips 81 and 8?., respectively, to provide sealed passages to bridge the gap 52 and to carry the oil through the outer end openings of ducts 78 and 79 to the bearing race, the bearings, the opposite sides of the wheel and to the chain. While the form shown illustrates a bifurcated passage means consisting of ducts 78 and 79, a single passage, such as 73, would be feasible to supply a sufcient amount of oil through the bearing raceto both sides of the wheel and to the chain. The two channel members 81 and 82 are spaced laterally outwardly of the wheel a slight amount, as are the outer plates 32 and 33, so as to not interfere with its rotation and so as to permit the easy flow of oil from the bearing race upwardly and downwardly on the surface of the Wheel and onto the chain.

When the lubricating oil system in the engine is operating, it forces oil through duct 65 into the sintered ilter 70 and the passage 71 and then into the main passage 73.

From the end of passage 73 at bore 77, the oil flows later-v ally to both sides into the ducts 78 and 79 and then intoboth sides of the bearing race 80 so as to lubricate the bearings. Because the wheel is rotating, the oil is carried outwardly on it, and on the outer plates 32 and 33, by centrifugal force to the chain links wherever they contact the wheel as they travel from the top to the underside of the blade into their cutting position.

It is clear that the present invention of a chain saw having a lubricating oil system which supplies oil directly to that portion of the saw chain which is about to be engaged in the cutting action may take various forms in various chain saw blade constructions without departing from the principles disclosed herein, f

I claim:

l. For use in a chain saw blade on which a saw chain is carried and guided as it is driven by an engine having lubricating oil supply means, said blade comprising a central elongated at plate having on each of its two flat opposite sides an outer flat plate, said blade having an inner end portion securable to a saw driving engine and having an opposite end portion to extend longitudinally outwardly from said engine, said central plate having opposite transverse portions extending transversely outwardly of said outer plates at both transverse edges to form a chain track, said outer plates extending longitudinally outwardly from said central plate at said opposite end; a flat-sided rotatable wheel of substantially the same thickness as said central plate mounted longitudinally outwardly of said central plate on bearings and supported on an axle fitted in said outer plates adjacent said opposite end of said blade; a gap extending transversely between said wheel and said opposite end of said central plate, said chain being adapted to be carried and guided on said chain track on said centralplate and on said wheel outwardly of said central plates; a lubricating system comprising lubricating passage means extending longitudinally within said blade, said passage means being adapted to be connected with lubricating oil supply means in said engine at said inner end portion to supply lubricating oil to said bearings and said chain extending around said wheel, said passage means comprising a conduit extending longitudinally in said central plate, said passage means being laterally bifurcated adjacent the opposite end portion of said central plate to extend intoan outer duct in each of said outer plates, said ducts bridging said gap and having open outer ends adjacent said bearings outwardly of said central plate; and the inner end of said passage means being bifurcated transversely to join two transversely spaced inlets, said inlets extending laterally through saidl blade, each of said inlets having a ilter therein extending from the outer side of one outer plate to the outer side of the other outer plate.

2. For use in a chain saw blade on which a saw chain is carried and Iguided as it is driven by an engine having lubricating .oil supply means, said blade comprising a central elongated at plate having on each of its two dat opposite sides an outer flat plate, said blade having an inner end portion securable to a saw driving engine and having an opposite end portion to extend longitudinally outwardly from said engine, said outer plates extending longitudinally outwardly from said central plate at said opposite end; a flat-sided rotatable wheel mounted on bearings'and supported on an axle between said plates longitudinally outwardly of said central plate and adjacent said opposite end, said bearings being in the form of roller discs tted between said two outer plates and positioned radially inwardly of said Vwheel and radially outwardly of said axle; a gap extending transversely between said wheel and said opposite end of said central plate, said chain being adapted to be carried and guided on said blade and on said wheel; a lubricating system comprising lubricating passage means extending longitudinally within said blade, said passage means being adapted to be connected with lubricating oil supply means in said engine at said inner end portion and to supply lubricating oil to said bearings and said chain extending around said wheel, said passage means comprising a groove extending longitudinally in said central plate and being laterally bifurcated adjacent the opposite end portion of said central plate to extend into a duct portion in each of said outer plates, said duct portions bridging said gap and having open outer ends adjacent said bearings outwardly of said central plate, said duct portions being formed by a laterally inwardly directed channel-shaped groove in said outer plates and a laterally outwardly directed channel member fitted in each of said inwardly directed channels; and the inner end of said passage means being bifurcated transversely to join two transversely spaced inlets, said inlets extending laterally through said three plates.

3. For use in a chain saw blade on which a saw chain is carried and guided as it is driven by an engine having lubricating oil supply means, said blade having an-inner end securable to a saw driving engine and having an opposite end to extend longitudinally outwardly from said engine, said blade having a rotatable wheel mounted on bearings and supported on an axle carried on said blade adjacent its opposite end, said bearings being laterally enclosed by .opposite end blade portions and positioned radially inwardly of said wheel Iand radially outwardly of said axle, said wheel being longitudinally spaced from a portion of said opposite end to permit rotation, said chain being adapted to be carried and guided on said blade and on said wheel, a lubricating system comprising: a lubricating oil passage extending longitudinally within said blade, said passage being adapted to be connected with lubricating oil supply means in said engine at said inner end and to supply lubricating oil to said bearings and said chain extending around said wheel, said passage being laterally bifurcated adjacent said opposite end of said blade to extend into parallel laterally spaced ducts in said blade laterally outwardly of said wheel, said ducts bridging said space and having open outer ends in communication with said bearings and said wheel longitudinally outwardly of said space; and the inner end of said passage means being bifurcated transversely to join two transversely spaced inlets, said inlets extending laterally through said blade so that said blade is reversible on said chain saw engine.

References Cited in the le of this patent UNITED STATES PATENTS 2,391,730 Melvin et al Dec. 25, 1945 2,747,945 Fulton May 29, 1956 2,748,810 Strunk June 5, 1956 2,896,746 Gudmundsen July 28, 1959 3,010,538 Strunk Nov. 28, 1961 FOREIGN PATENTS 1,047,905 France July 29, 1953 

